The invention relates to detection devices and methods, and particularly pertains to the detection and classification of biological particles including bacterial endospores, various species of vegetative bacteria, various harmless background particles etc. This will be accomplished by comparing information extracted from excitation-emission graphs for unknown samples from the environment with information from such graphs obtained from experiments with known samples including but not limited to comparing information from excitation-emission graphs taken from a normal strain graphs taken from a normal strain dipicolonic acid (DPA+) of Bacillus subtilis spores and from spores of a mutant strain (DPA−) derived from the same DPA+ strain, excitation-emission graphs of the pure chemicals such as CaDPA, DPA and tryptophan which may be components of biological particles. CaDPA and DPA are usually found in bacterial endospores. Further information from excitation-emission graphs taken for various species of vegetative bacteria and for spores from different species of bacteria will also be utilized as well as excitation-emission graphs from various background materials expected to be found at times in aerosols or dust.
When released into the environment, endospores can survive extreme heat, lack of water and exposure to many toxic chemicals and radiation. Most of the water present in the cell cytoplasm is eliminated during spore formation. Such endospores do not generally carry out metabolic reactions. A significantly large amount of the organic acid dipicolonic acid (found in the spore core), is accompanied by a large number of calcium ions. Calcium ions (Ca.sup.++) are combined with the dipicolinic acid as seen below.
The calcium-dipicolinic acid complex represents about ten percent of the dry weight of the endospore. As would be understood, such endospores can readily become airborne. If present in an area of human occupancy, such as an office building, home or the like, certain endospores can be life threatening when present through inadvertence, accident or deliberately introduced by bioterrorists.
While various types of detection methods for certain deadly endospores such as Bacillus anthracis (anthrax) are known, current methods generally consist of collecting specimens from office buildings, homes or outdoor locations and delivering them to various instruments which at present take from one to several hours or more to complete the analysis. Thus, those unfortunate enough to be exposed to deadly endospores (such as anthrax) or alternatively with other pathogenic bacteria may have the delivery of medical countermeasures significantly delayed so as to exacerbate their condition. Further, rapid early classification such as provided by the present invention can be a trigger to determine where to deliver samples for further interrogation by more time-consuming methods.
Therefore, in view of the need for a speedy and continuous method of detecting anthrax and other pathogenic bacteria, which may be, for example, airborne in public buildings, the present invention was conceived and one of its objectives is to provide a device and method whereby the presence of bacillus anthracis or the presence of other classes of bacteria can be easily and inexpensively be indicated as likely.
It is an objective of the invention to provide a device for detecting biological particles when their presence is suspected; for indicating when bacterial endospores are present; and for providing preliminary classification of other bacteria (e.g. Gram positive or Gram negative) when vegetative bacteria are present.
It is another objective of the present invention to provide a device and Method for indicating when bacterial endospores are present; and for providing preliminary classification of other bacteria (e.g. Gram positive or Gram negative) when vegetative bacteria are present which is easy to operate and requires little specialized training.
It is yet another objective of the present invention to provide a method for indicating when bacterial endospores are present and for providing preliminary classification of other bacteria (e.g. Gram positive or Gram negative) when vegetative bacteria are present, both of which are relatively inexpensive to operate continuously for twenty-four hours a day. The invention may optionally comprise triggering an alarm when a suspected biological threat is present. The suspected biological threat may include one or more types of bacterial endospores or vegetative bacteria. Various other objectives and advantages of the present invention will become apparent to those skilled in the art as a more detailed description is set forth below.